A modified method for the evaluation of spectral parameters of 4f→ 4ftransitions in 'Pr(III) and Nd(III) complexes

Abstract

A modified method has been proposed for evaluating the energy interaction, spin-orbit interaction, bonding, nephelauxetic, oscillator strength and Judd-Ofelt parameters for Pr³⁺ and Nd³⁺ = systems. The parameters have been evaluated using an HP-1000/45 computer and by assuming certain boundary conditions. By this method, the root mean square (rms)values for the energies are reduced to the order of -20-50 cm^-1 as compared to the values ~ 200-250 cm^-1 obtained by earlier workers. For Pr(III) complexes, two correction parameters <em>T</em>₇; (positive correction) and <em>T</em>₈ (negative correction) are introduced which bring down the rms values in oscillator strength and <em>T</em>_λ parameters and also reduce the negative values observed for <em>T</em>₂ parameter. A new hypersensitive band ⁴<em>I</em>_9/2 → ⁴<em>F</em>_5/2 is observed apart from the usual hypersensitive ⁴<em>I</em>_9/2 → ⁴<em>G</em>_5/2 band in the case of Nd(III)-nucleoside/nucleotide systems and this has been also taken into consideration in the evaluation of parameters. A new correction parameter <em>T</em>_c is used in explaining the spectral data of Nd(III); it makes the interpretation of spectral data in solution more meaningful. This method has been tested for the spectra of ~ 200 complexes of Pr³⁺ and an equal number of Nd³⁺ complexes.